10 best us cities to visit on vitreous humor see eye. vocalization n. the production of sounds by means of vibrations of the vocal cords, as in speaking, babbling, singing, screaming, and so forth. vocalize vb. voice-onset time in phonetics, the brief instant that elapses between the initial movement of the speech organs as one begins to articulate a speech sound and the vibration of the vocal cords. Voice-onset time has been the subject of intense research in adult and infant speech perception because of evidence that this continuous acoustic dimension is perceived categorically (see categorical perception). volley theory the principle that individual fibers in an auditory nerve respond to one or another stimulus in a rapid succession of rhythmic sound stimuli, whereas other fibers in the nerve respond to the second, third, or nth stimulus. 10 best us cities to visit 2016.